Rescuers pulled a 30-year-old man from the surf in Long Beach on Saturday afternoon after he stripped to his underwear and went into the water, said City Manager Charles Theofan.
The unidentified man went into cardiac arrest shortly after being pulled out, Theofan said.
"He's still alive, but it doesn't look good," Theofan said.
Theofan did not know why the man went into the water. Lifeguards went off duty after Labor Day.
The man went in the water near National Boulevard, Theofan said.